Vast quantities of cellulosic materials occur universally as surplus and waste residues of agricultural operations. In particular, they occur in the form of cellulosic crop residues, usually the straws of cereal grains, for example, wheat, barley, corn, rice, oats and rye (sometimes called stovers, for example, cornstover) and sugarcane bagasse, and in the form of animal manure, such as, cattle, swine and poultry manure.
There have been prior suggestions to convert components of these waste materials to useful proteinaceous materials by fermentation, but generally speaking such prior procedures have been uneconomic and/or do not utilize all the components of the waste material.